bigredbaja

My 496 is not the HO version and i was going to have the cam swapped for the HO Cam or Raylar spec cam and have the ECM reflashed. I was told the HO had a forged crank and my Mag has a cast crank and the modifacations could shorten the engine life. I know you generally hear the 496's are all cast internals but didnt some early 496's have a forged crank in both MAG and HO set ups? I thought i remembered reading that somewhere.

Keith Atlanta

All cast. Event he early 496 HO's had very few with forged cranks. You have to understand this isnt your fathers cast crank. They are rated very high. Whipple ran the cast cranks up to 800 HP in tests. I can assure you you wont be over 450 HP with any cam swap. Seriously consider the valve springs and get the Raylar roller rockers too.

pqjack

been told the same thing by Ray....strong crank,good for 750-800 hp

Donskihp

Before I wippled my 496HO I called Merc and asked them, they told me mine had a forged crank. When I put Raylar Heads and raylar Cam on mine, Larry (Raylar) told me that Merc never had forged cranks in them. However he also told me that the cranks were very heavy and could handle about anything you can throw them

Keith Atlanta

Your concern shouldnt be the crank. The pistons are weak for a high performance application. Make sure you upgrade them.

bigredbaja

Sounds like i will be safe all i am really considering is the HO Cam, ECM reflash and adding Dana exhaust, i did have one engine buildertell me i would be ok with the pistons up to the point you change the compression ratio of the engine.
Thanks for the feedback!

MER Performance

The HO crank is a Nodular crank.
The pistons are the greatest issue, hypereutectic pistons,9.0:1 CR, 1.040 wrist pin offset .030", interference fit. Caming profile of piston skirt is poorly machined, ring set are super stiff, FRICTION!
Rod bearings same as BBC
Mains bearings; lower same as BBC, Upper has 45 degree offset and tang is narrower than BBC.
King Bearings informed me the are releasing replacement main bearings in March, due to the over-seas, market demand. Lets see what happens?
I am working on the same project 496 with Whipple.
Changing rods, BBC H Beam
Sample piston, sent to my engineer @ CP using a 4032 alloy, .990 pin, no .030 offset, lowering CR.
Marine Kinetics CAM
Heads replaced with Dart, Wanted to use Raylar( No reply back from PM sent)
ARP head studs, 10mm ARP rocker studs, Scorpion rocker arms
The oil pan has a pretty impressive windage design.

I'll let you know more as it goes. Mark